Hemophilia patients suffer from increased bleeding due to deficiencies in coagulation cascade factors such as Factor VIII (Hemophilia A), Factor IX (Hemophilia B), and Factor XI (Hemophilia C). There is a large unmet need for treatment of hemophilia patients, including those currently treated with recombinant FVIII, e.g., “inhibitor” patients. Some but not all hemophilia A patients with Factor V Leiden mutation have significantly milder disease with reduced bleeding episodes, arthropathy and rFVIII requirements (reviewed Franchini and Lippi, Thromb Res, 2010). Some patients with a Factor V Leiden mutation have activated Protein C resistance. (Nichols et al. (1996) Moderation of hemophilia A phenotype by the factor V R506Q mutation. Blood 88:1183).
Protein C (autoprothrombin IIA and blood coagulation factor XIV) is a zymogene encoded by the PROC gene. Greater than 85% of circulating Protein C is in the zymogene form. After cleavage by thrombin, activated Protein C (APC) is a serine protease with anticoagulant and cytoprotective functions. The half-life of APC is only 15 minutes.
Double-stranded RNA molecules (dsRNA) have been shown to block gene expression in a highly conserved regulatory mechanism known as RNA interference (RNAi). WO 99/32619 (Fire et al.) discloses the use of a dsRNA of at least 25 nucleotides in length to inhibit the expression of genes in C. elegans. dsRNA has also been shown to degrade target RNA in other organisms, including plants (see, e.g., WO 99/53050, Waterhouse et al.; and WO 99/61631, Heifetz et al.), Drosophila (see, e.g., Yang, D., et al., Curr. Biol. (2000) 10:1191-1200), and mammals (see WO 00/44895, Limmer; and DE 101 00 586.5, Kreutzer et al.).